Late Fee Calculator
Calculates late payment penalties and accrued interest on overdue invoices at specified rates
The original invoice amount
Number of days past the payment due date
Annual interest rate applied to overdue invoices
Optional one-time flat fee for late payment
Interest accrued based on days overdue
One-time flat late fee amount
Combined interest and flat fee charges
Original invoice amount plus all late fees
Frequently Asked Questions
How do I calculate late fees on an invoice?
Late fees typically combine a flat fee and/or interest. Interest is calculated as: Invoice Amount x Annual Rate x (Days Overdue / 365). For example, $5,000 at 18% annual interest for 30 days = $5,000 x 0.18 x (30/365) = $73.97.
What is a typical late fee for invoices?
Common approaches include 1-2% monthly interest (12-24% annually), a flat fee of $25-50, or a combination of both. Check your state or country's usury laws, as maximum allowable rates vary by jurisdiction.
Are late fees legally enforceable?
Generally yes, if they are disclosed in the original contract or invoice terms before work begins. The fee must be reasonable and comply with local usury laws. Having clear payment terms in writing protects your right to collect.
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